Nervous System

Question 1

Neurons Location

Answer 1

Nervous System

Question 2

Neurons

Answer 2

Specialized cells found throughout nervous system that transmit information through electrical signaling within the body

Question 3

Neuron Function Dependence

Answer 3

Depends on membrane structure + regulated transport of ions across plasma membrane

Question 4

Neuron Structural Components

Answer 4

Dendrite; Nucleus; Cell body; Axon; Myelin sheath; Node of Ranvier; Schwann cell; Axon terminal

Question 5

Dendrites Structure

Answer 5

Branch-like structures with cell body with nucleus

Question 6

Dendrites Function

Answer 6

Receive incoming signals from other cells

Question 7

Axon Structure

Answer 7

Long wire attached to cell body

Question 8

Axon Function

Answer 8

Conducts electrical signals along axon membrane

Question 9

Myelin Sheath Structure

Answer 9

Sleeve wrapped around each nerve cell (neurons)

Question 10

Myelin Sheath Function

Answer 10

Insulates axon + increases speed of signal transmission

Question 11

Nodes of Ranvier Structure

Answer 11

Gaps in myelin sheath

Question 12

Nodes of Ranvier Function

Answer 12

Location where ions cross the membrane

Question 13

Axon Terminal Structure

Answer 13

Branch-like structure at the end of the axon

Question 14

Axon Terminal Function

Answer 14

Transmits signals to other cells

Question 15

Neuron Function

Answer 15

Electrical Signaling (use 2 types of signals to communicate)

Question 16

2 Types of Signals

Answer 16

Electrical signals + Chemical signals

Question 17

Electrical signals

Answer 17

Used for long-distance communication along neuron’s membrane; Generated by regulated ion movement across neuron’s plasma membrane

Question 18

Chemical signals

Answer 18

Used for short-distance communication between cells

Question 19

Information Flow

Answer 19

Flow from presynaptic cell (neuron) to postsynaptic cell (neuron / muscle / gland cell)

Question 20

Electrical + Chemical signals

Answer 20

Electrical signals travel along the neuron + chemical signals act at synapses

Question 21

Presynaptic Cell

Answer 21

Cell that delivers the signal to the synapse

Question 22

Resting potential

Answer 22

Membrane potential of a neuron not sending signals; Electrical charge difference across a cell’s membrane when it’s inactive

Question 23

Membrane Potential

Answer 23

Voltage (difference in electrical charge) that each cell has across its plasma membrane; Changes in MP act as signals + allow neurons to transmit + process information

Question 24

Sodium-Potassium Ions

Answer 24

More Na+ ions are outside neuron + more K+ ions are located inside neuron → Inside of neuron is more negatively charged than outside → Create difference in electrical charge across plasma membrane

Question 25

Chemical Potential Energy

Answer 25

Stored energy in K+ and Na+ concentration gradients across plasma membrane maintained by sodium-potassium pumps using ATP

Question 26

Sodium/Potassium (Na+/K+) Pump

Answer 26

Active transport protein that uses ATP to maintain ion gradients (*not action potential) = Keep Na+ high outside and K+ high inside

Question 27

Na+ / K+ Pump Cycle

Answer 27

3 Na+ are pumped out, 2 K+ are pumped in

Question 28

Action Potential Cycle

Answer 28

Resting state → Depolarization → Rising phase of action potential → Falling phase of action potential → Undershoot

Question 29

Depolarization

Answer 29

Cell becomes more positive: Stimulus opens voltage-gated Na⁺ channels → Na⁺ rushes into the cell due to both concentration and electrical gradients → Inside is less negative + membrane potential rise

Question 30

Repolarization

Answer 30

Cell return to polarized resting state: Voltage-gated Na⁺ channels close (inactivated) + Voltage-gated K⁺ channels open → K⁺ flows out of the cell, down its concentration gradient → Membrane potential moves back toward negative values

Question 31

Action Potential

Answer 31

Fast + temporary change in electrical charge of neuron’s membrane that allows it to send a signal along its axon

Question 32

Action Potential Cause

Answer 32

Neuron’s membrane briefly becomes positive inside (depolarizes) and then returns to negative (repolarizes), caused by controlled movement of ions like Na⁺ and K⁺.

Question 33

Action Potential Movement Along Axon

Answer 33

Signal spreads along the axon; Ions do not travel down its length

Question 34

Synapse

Answer 34

Connection point between two neurons

Question 35

Synaptic Transmission Process

Answer 35

Nerve impulse (action potential) travels down axon → Voltage-gated Ca²⁺ channels open in axon terminal → Ca²⁺ influx trigger release of neurotransmitter (NT) → NT released from its vesicle + cross synaptic cleft + binds to receptor on postsynaptic dendrite → NT binding opens ion channels in postsynaptic cell → Can initiate new action potential if threshold is reached

Question 36

NT Definition + Function + Location

Answer 36

Chemical messengers (NT) carries information between neurons at chemical synapses

Question 37

Presynaptic Neuron (NT)

Answer 37

Synthesizes + packages NT in synatic vesicles located in synaptic terminal

Question 38

Action Potential at Synapse

Answer 38

Triggers NT release into synaptic cleft via exocytosis

Question 39

Crossing of NT

Answer 39

NT diffuses across synaptic cleft + is received by postsynaptic cell → Convert signal back into electrical response

Question 40

NT Types

Answer 40

Different NT produce different effects; All use same synaptic mechanism

Question 41

Neurotransmitters (NT)

Answer 41

A single NT can bind to many different receptor types → Produce different effects in different cells; Postsynaptic responses end when NT are cleared from synaptic cleft

Question 42

Removal of NT

Answer 42

Diffusion away from synapse; Enzymatic breakdown; Reuptake into presynaptic neuron